1. Field of the Invention
The present invention generally relates to a technology for controlling access to a storage device. The present invention specifically relates to a technology for preventing unauthorized access to a storage device.
2. Description of the Related Art
Universal serial bus (USB) memories have become very popular as portable storage devices because of their high capacity and high portability. The USB memories, however, have a disadvantage that they can be easily stolen, misplaced, or lost, and the information in the USB memories can be misused. Therefore, there is a need of some means for preventing leakage of information in the USB memories.
One approach is to prepare a private area in the USB memory and limit access to the private area based on user authentication so that information in the private area is prevented from leaking. Such a technique is disclosed, for example, in Japanese Patent Application Laid-Open No. 2004-151785. In this approach, however, when a user is determined to be authenticated, the private area becomes accessible to all the process, authorized and unauthorized. An unauthorized process may access the information in the private area and misuse the information. For example, when the USB memory is connected to a third-party computer or a computer that has not been virus-checked, an unauthorized process running in such a computer may access information in the private area and misuse the information. Thus, there is a need of a technology for preventing access to the USB memories by unauthorized processes.